Mixed multiaxial pivoting head

ABSTRACT

The invention relates to a multiaxial pivoting head intended to be mounted at the end of moving arm ( 22 ) of a machine-tool, said pivoting head comprising, on the one hand, a yoke ( 30 ) including a support shaft ( 32 ), said yoke being able to be mounted rotatably on said arm ( 22 ), while said support shaft ( 32 ) extends substantially perpendicular to said arm ( 22 ), and on the other hand, at least two working members ( 38, 40 ) installed on said support shaft ( 32 ) in positions angularly offset relative to one another, said support shaft ( 32 ) being rotatable to be able to alternately bring each of said at least two working members ( 38, 40 ) between a position retracted inside said yoke ( 30 ) and a working position protruding from said yoke. One of said at least two working members ( 40 ) is a waterjet cutting device.

The present invention relates to a multiaxial pivoting head for amachine-tool, and in particular for a so-called five-axis machiningtool.

This type of machine-tool includes a moving arm situated at the end of arobot or mounted on a gantry, and a pivoting head mounted at the end ofsaid moving arm. The pivoting head includes a fork block forming a yoke,mounted rotatably at the end of the arm, and the fork block is equippedwith a support shaft which, in turn, extends substantially perpendicularto the direction defined by the arm. The support shaft is thus equippedwith at least two spindles able to respectively receive a work tool. Thespindles extend in planes substantially parallel to one another andperpendicular to the support shaft; they may also extend in a sameplane. They are furthermore angularly offset relative to one another onthe support shaft. In this way, the tools can be moved in an alternatingmanner, between a working position in which they extend protruding fromthe fork block and a retracted position in which they are brought insidethe fork block, while driving the rotation of the support shaft in onedirection, then in an opposite direction. Reference may in particular bemade to document EP 1,405,691 A1, which describes a pivoting headallowing such an implementation.

Thus, by equipping the spindles with two different types of tool, it iseasy to successively machine a part, for example crudely, then moreprecisely, with practically no downtime, by switching the position ofthe two tools through the simple rotation of the support shaft.

For certain complex parts, it is necessary to machine them, but also toperform prior cutouts or clipping. These cutouts are, under certaincircumstances, done using a waterjet cutting device. Consequently, theparts are first installed on a specific machine-tool, having a movinghead equipped with an injection nozzle, and a pressurizing pump to beable to inject pressurized water, usually with an abrasive. Such amachine is in particular equipped with a facility for recovering sludgeresulting from spraying a mixture of water, abrasive and material.

Consequently, when the cutout must be done prior to machining, the partsshould, in a first phase, be brought under the waterjet machine-tool,then next brought under the machining machine-tool. The transfer time ofthe part is then added to the cutting out and machining time.

One problem that arises and that the present invention seeks to resolveis to be able to reduce the treatment times for the parts, and thus toreduce the costs.

To that end, the present invention proposes a multiaxial pivoting headintended to be mounted at the end of moving arm of a machine-tool, saidpivoting head comprising, on the one hand, a yoke including a supportshaft, said yoke being able to be mounted rotatably on said arm, whilesaid support shaft extends substantially perpendicular to said arm, andon the other hand, at least two working members installed on saidsupport shaft in positions angularly offset relative to one another,said support shaft being rotatable to be able to alternately bring eachof said at least two working members between a position retracted insidesaid yoke and a working position protruding from said yoke. One of saidat least two working members is a waterjet cutting device.

Thus, one feature of the invention lies in the implementation of awaterjet cutting device of the support shaft inside the yoke, or forkblock, the same way as the machining tool, so as to be able to cut out apart, then machine it without having to disassemble it and without evenhaving any downtime. The waterjet cutting device is thus brought from aworking position to a position retracted inside the yoke, by rotatingthe support shaft, while the other working tool is consequently broughtinto the working position. In this way, a single machine-tool structureis necessary, which reduces the installation cost, but furthermore, thecutting out and machining time is shortened, since no part disassemblyis necessary. Additionally, the positioning precision of the cuttinghead and the machining head is greatly improved due to the use of a samesupport axis to support both. Furthermore, since it is possible to gofrom a cutting out phase to a machining phase without downtime, it isalso conversely possible to go from a machining phase to a cutting outphase. From there, when the part has large dimensions, time is saved onthe movements of the tooling head.

According to one particularly advantageous feature of the invention,said waterjet cutting device includes an injection nozzle and a recoveryreceptacle mounted across from said injection nozzle. In this way, thecutting sludge is recovered in particular incorporating water, abrasiveand material debris, during the cutting out phase, owing to the recoveryreceptacle, which is situated across from the injection nozzle in theextension thereof. Indeed, the multiaxial pivoting head is driven,relative to the part to be cut out, so as to bring the injection nozzleon one side of the part and the reception receptacle on the other side.During the travel of the jet of water and abrasive particles, said jetcrosses through the part and finishes in the receptacle. From there, thecutting out does not cause any projection of water or sludge, whichmakes it possible to implement the device on the support shaft, close tothe other spindle, which is driven by an electric motor. Additionally,the abrasive particles and the water from the jet do not penetrate theinside of the spindle, which could damage the mechanical elements byabrasion as well as corrosion.

Preferably, said injection nozzle extends in an inclined directionrelative to the tangent to said support shaft. Thus, the waterjetcutting device includes a tubing that extends along a tangent to thesupport shaft, and the injection nozzle extends in the extension of thetubing along a direction inclined relative to the tubing. In this way,it is easier to perform the cutout in withdrawn zones of the part, aswill be explained in more detail in the continuation of the description.

According to one particularly advantageous embodiment, said waterjetcutting device comprises a discharge duct connected to said recoveryreceptacle. In this way, the cutting sludge is suctioned continuously asit is produced. It is then possible to operate the waterjet cuttingdevice irrespective of the orientation of the nozzle and the receptacle,in particular when the receptacle is situated above the nozzle relativeto the ground.

Furthermore, said waterjet cutting device advantageously comprises anabrasive particle intake duct connected to said injection nozzle. Inthis way, the pressurized water intake circuit is independent and isdirectly connected to the injection nozzle, while the abrasive particlesare introduced into the waterjet through the intake duct at theinjection nozzle.

According to one particularly advantageous alternative embodiment, saidwaterjet cutting device comprises a V-shaped maintaining member havingtwo branches to keep said recovery receptacle opposite said injectionnozzle. Advantageously, said V-shaped maintaining member is mountedrotatably mobile around an axis substantially perpendicular to saidsupport shaft. Thus, said V-shaped maintaining member defines a meanplane and is connected to said support shaft such that said mean planeextends substantially perpendicular to the support shaft. The axisaround which the V-shaped maintaining member is able to rotateintersects the two branches. In this way, during the cutting phase, theV-shaped maintaining member can be rotated by a predetermined amplitude,so as to be able to facilitate the movement of the pivoting head as afunction of the geometry of the part.

Preferably, according to this alternative embodiment, said V-shapedmaintaining member further comprises a fastening platen arranged on oneof said two branches to be able to fasten said V-shaped maintainingmember to said support shaft. As will be explained in more detail in thecontinuation of the description, the platen has controllable lockingmembers making it possible to interchange the V-shaped maintainingmember. Indeed, different types of V-shaped maintaining members areprovided, so as to be able to obtain different distances between theinjection nozzle and the recovery receptacle to be able to cut out partswith different thicknesses and different geometries.

Consequently, the other of said branches advantageously receives saidrecovery receptacle, which is open toward the other branch.

According to one particularly advantageous embodiment of the invention,said V-shaped maintaining member includes a passage pathway emerging insaid receiving receptacle and in said fastening platen to form a portionof said discharge duct. Thus, the passage pathway includes, at thefastening platen, a connector intended to be connected to the inlet ofanother discharge duct portion, when the fastening platen is fastened onthe support shaft.

Furthermore, the multiaxial pivoting head further comprises a waterpressurizing device coupled to said waterjet cutting device, and saidwater pressurizing device is able to be housed inside said moving arm.In this way, the water pressurizing device is situated as close aspossible to the injection nozzle, which makes it possible to decreasethe pressure losses compared with waterjet cutting facilities accordingto the prior art, where they are far away from one another.

Other particularities and advantages of the invention will emerge fromreading the following description of one particular embodiment of theinvention, provided for information but non-limitingly, in reference tothe appended drawings, in which:

FIG. 1 is a diagrammatic perspective view of a machine-tool including amultiaxial pivoting head according to the invention;

FIG. 2 is a partial diagrammatic perspective view of an element of themultiaxial pivoting head according to the invention according to a firstembodiment;

FIG. 3 is a partial diagrammatic perspective view of the elements shownin FIG. 2 from another viewing angle;

FIG. 4 is a partial diagrammatic perspective view of the elements shownin FIG. 2 in a first working position;

FIG. 5 is a partial diagrammatic perspective view of the elements shownin FIG. 2 in a second working position;

FIG. 6 is a diagrammatic perspective view of the multiaxial pivotinghead according to the invention according to a second embodiment, in theworking position;

FIG. 7 is a diagrammatic view of the multiaxial pivoting head shown inFIG. 6, in an idle position; and

FIG. 8 is a detailed view of an element shown in FIGS. 6 and 7.

FIG. 1 illustrates a machine-tool 10 comprising a gantry 12 having anupper crosspiece 13 extended above a worktable 14. The latter makes itpossible to immobilize a complex part 16 having a curve 18 and parallelstiffeners 20. The machine-tool 10 comprises a vertical arm 22 shown incutaway and connected to the gantry 12 by a carriage 24 making itpossible to drive the arm 22 in a direction parallel to the crosspiece13. Furthermore, the arm 22 is translatable on its own axis, whichextends vertically.

The arm 22 has an end 26 on which a multiaxial pivoting head 28 ismounted. It comprises a yoke 30 forming a fork block, and mountedrotating at the end 26 of the arm 22 around the vertical axis of the arm22. It additionally comprises a support shaft 32 mounted rotating insidethe yoke 30, along an axis substantially perpendicular to the verticalaxis of the arm 22 and that will be described in more detail below inreference to FIGS. 2 to 4.

FIG. 2 shows the support shaft 32 able to be installed inside the yoke30 or fork block to be able to be rotated around the horizontal axis B.The support shaft 32 has two opposite circular flanks 34, 36 and betweenthe two, part of a spindle 38 extending along an axis tangential to thesupport shaft 32 perpendicular to the axis B and able to receive a worktool, and on the other hand a waterjet cutting device 40. The waterjetcutting device 40 extends in a position substantially diametricallyopposite the spindle 38 relative to the support shaft 32.

Reference will be made to FIG. 3, providing a more detailed view of thewaterjet cutting device 40. It comprises a V-shaped maintaining member42 having two branches, a free branch 44, and a fastening branch 46ending with a fastening platen 48. It includes an injection nozzle 50mounted in the extension of a tubing 52. The tubing 52 extendstangentially to the support shaft 32, while the injection nozzle 50extends in a direction inclined relative to the tubing 52, for examplecomprised between 150° and 170°. The fastening platen 48 has anindentation 54, and it is connected to the support shaft 32 such thatthe tubing extends through the indentation 54, while the injectionnozzle 50 extends toward the end of the free branch 44, and morespecifically toward a receiving receptacle 56 secured to the end of thefree branch 44. The receiving receptacle 56 has a cylindrical shape opentoward the injection nozzle 50. It is made from a high-strength materialand is connected to a discharge duct 58, which extends inside the freebranch 44 to next be able to extend through the pivoting head, thentoward a recovery reservoir. Furthermore, the discharge conduit 58 isintended to be placed in a vacuum using a suction pump, not shown, aswill be explained below.

Furthermore, the fastening platen 48 is fastened on a crown 60 showntransparently through the support shaft 32, the rotation of the crown 60being able to be controlled using an electric actuator 62. In this way,the V-shaped maintaining device 42, as a whole, is able to be rotated.Advantageously, the tubing 54 supporting the injection nozzle 50 isrotatably secured to the crown 60 to be able to drive the receivingreceptacle 56 over the course of the driving of the injection nozzle 50.In this way, the receiving receptacle 56 remains in the axis of theinjection nozzle 50 irrespective of the position of the nozzle 50.

Furthermore, the injection nozzle 50 has a lateral connector 64 to beable to connect an abrasive particle intake conduit 66 that appears inFIG. 5. In this FIG. 5, the support shaft 32 is engaged between twofacing flanges 68, 70 of the yoke 30 so as to be able to pivot aroundthe horizontal axis B.

This figure also shows, on the one hand, the V-shaped maintaining member42 equipped with the receiving receptacle 56, and the injection nozzle50, which both extend protruding from the yoke 30, and on the otherhand, the complex part 16 provided with its stiffeners 20. It will benoted that the multiaxial pivoting head is adjusted such that theinjection nozzle 50 and the receiving receptacle 56 are situated oneither side of the stiffener 20. The axis of the injection nozzle 50 isthen substantially perpendicular to the stiffener 20.

Before describing the operation of the multiaxial pivoting head 28, wewill return to FIGS. 1 and 2, showing a water pressurizing devicecoupled to the waterjet cutting device. More precisely, in FIG. 1, theend 26 of the arm 22 houses, inside, a pressurizing device 72 includingan intensifier and an accumulator that are directly connected to theinjection nozzle 50 using a high-pressure conduit 74.

Consequently, the water is brought to the pressurizing device and theintensifier using a low-pressure hose 76, while the pressurized oil isbrought using two medium-pressure hoses 78. The water circuit includes abooster pump 80, and a water supply 82, while the oil circuit includes ahydraulic pump 84, a tank 86 and a distributor 88.

The hydraulic circuit makes it possible to drive, alternatingly, apiston in a chamber, and from there pressurized water, according to awell-known technique, up to pressures from 4000 to 6000 bars. Thus,owing to the proximity of the pressurizing device 72 and the injectionnozzle 50, the pressurized water intake conduit is consequently shorter,and from there, the pressure losses are lower. Consequently, for a givenpressure, more effective cutting is obtained.

The rigid pipe lengths with a significant curve radius that arenecessary on large machines are eliminated, thereby avoiding fragilebutt jointing by very high-pressure connection.

Reference will again be made to FIG. 4 illustrating the multiaxialpivoting head in the cutting position of the stiffener 20. Thus, theimplementation of the pressurized water through the nozzle 50 and theconcomitant injection of abrasive particles through the lateralconnector 64 cause cutting of the stiffener 20. Furthermore, thedischarge duct 58 connected to the receiving receptacle 56 is placed ina vacuum. In this way, the waterjet crosses through the stiffener 20,then ends up in the receiving receptacle 56 situated opposite it,driving the abrasive particles, debris from the material and lubricantswith it. The sludge thus formed is suctioned continuously through thedischarge duct 58. In this way, the essence of the projections due tothe waterjet are suctioned through the receiving receptacle 56.Consequently, the other elements of the pivoting head, and in particularthe mechanism of the support shaft 32 and the spindle 38, are notaffected. Owing to this recovery arrangement for the sludge, thewaterjet cutting device 40 may be arranged near the spindle 38.

The cutting of the stiffener 20 is done by translating the multiaxialpivoting head 28 parallel to the stiffener according to a predeterminedspeed.

After the cutting operation is complete, and when one wishes to carryout a machining step in the same zone of the complex part 16, it is theneasy to command the rotation of the support shaft 32 by about 180°, forexample during hidden time during the movement of the multiaxialpivoting head 28, so as to retract the waterjet cutting device 40, andto bring the spindle 38 equipped with a tool 90 to protrude from theyoke and into a working situation as illustrated in FIG. 5. This figureshows the multiaxial pivoting head 28 adjusted above the complex part16. The waterjet cutting device 40 is then inactive and housed insidethe yoke 30.

The tool 90 is precisely brought against the edge of a recess 92arranged in the complex part 16 so as to be able to trim said edge, forexample.

Conversely, when a machining phase is complete and a cutting operationis necessary in the environment near the location where the multiaxialpivoting head 28 is situated, the support shaft 32 is once again rotatedby about 180° in the opposite direction, so as to again make thewaterjet cutting device 40 operational.

Reference will be made to FIGS. 6 and 7 to describe the multiaxialpivoting head according to another embodiment. The elements identical tothe preceding embodiment or having the same functions bear the samereference, with a prime sign:

Thus, FIG. 6 shows the multiaxial pivoting head 28′ comprising a yoke30′ and a support shaft 32′ situated inside. The support shaft 32′ isequipped with a spindle 38′ and in a position substantiallydiametrically opposite a waterjet cutting device 40′. The latter has aninjection nozzle 50′ and, opposite it, a receiving receptacle 56′mounted on a V-shaped maintaining member 42′ that will be described inmore detail in reference to FIG. 8.

The V-shaped maintaining member 42′ has a free branch 44′, and afastening branch 46′ also forming the fastening platen 48. The latterhas an indentation 94 and centering 96, 98 and fastening 100, 102 pins.

The end of the free branch 44′ includes a receiving receptacle 56′, andinside the free branch 44′, a discharge duct portion, concealed here,extends, which emerges in the platen 48′ at a connector 104.

Thus, the V-shaped maintaining member 42′ will be able to be installedautomatically on the support shaft 32′, the injection nozzle 50′extending through the indentation 94, whereas on the one hand, thecentering spindles 96, 98 and fastening spindles 100, 102 engage inorifices provided to that end, and on the other hand, the connector 104of the discharge duct portion is automatically and tightly connected toanother portion of the discharge duct.

In this way, as illustrated diagrammatically in FIG. 7, different typesof V-shaped maintaining members 42′ will be installed in a rack and themultiaxial pivoting head 28′ will be able to be brought to a given typeof V-shaped maintaining member 42′ for automatic assembly. The types ofV-shaped maintaining members 42′ may differ, for example, by thedistance between the two branches, and consequently the distance betweenthe receiving receptacle 56′ and the injection nozzle 50′. This is forexample the distance between the first two maintaining members 106, 108shown in FIG. 7. The third 110 is not strictly speaking operational as atool and simply makes it possible to protect the injection nozzle 50′.The fourth 112 makes it possible to bear a measuring system and is alsonot operational as a tool. The last 114 is fully operational andincludes a motor making it possible to rotate the fastening platen 48′.

1. A multiaxial pivoting head intended to be mounted at the end ofmoving arm of a machine-tool, said pivoting head comprising, on the onehand, a yoke including a support shaft, said yoke being able to bemounted rotatably on said arm, while said support shaft extendssubstantially perpendicular to said arm, and on the other hand, at leasttwo working members installed on said support shaft in positionsangularly offset relative to one another, said support shaft beingrotatable to be able to alternately bring each of said at least twoworking members between a position retracted inside said yoke and aworking position protruding from said yoke; wherein one of said at leasttwo working members is a waterjet cutting device.
 2. The multiaxialpivoting head according to claim 1, wherein said waterjet cutting deviceincludes an injection nozzle and a recovery receptacle mounted acrossfrom said injection nozzle.
 3. The multiaxial pivoting head according toclaim 2, wherein said injection nozzle extends in an inclined directionrelative to the tangent to said support shaft.
 4. The multiaxialpivoting head according to claim 2, wherein said waterjet cutting devicecomprises a discharge duct connected to said recovery receptacle.
 5. Themultiaxial pivoting head according to claim 2, wherein said waterjetcutting device advantageously comprises an abrasive particle intake ductconnected to said injection nozzle.
 6. The multiaxial pivoting headaccording to claim 2, wherein said waterjet cutting device comprises aV-shaped maintaining member having two branches to keep said recoveryreceptacle opposite said injection nozzle.
 7. The multiaxial pivotinghead according to claim 6, wherein said V-shaped maintaining member ismounted rotatably mobile around an axis substantially perpendicular tosaid support shaft.
 8. The multiaxial pivoting head according to claim6, wherein said V-shaped maintaining member further comprises afastening platen arranged on one of said two branches to be able tofasten said V-shaped maintaining member to said support shaft.
 9. Themultiaxial pivoting head according to claim 8, wherein the other of saidtwo branches receives said recovery receptacle.
 10. The multiaxialpivoting head according to claim 4, wherein said waterjet cutting devicecomprises a V-shaped maintaining member having two branches to keep saidrecovery receptacle opposite said injection nozzle, and wherein saidV-shaped maintaining member includes a passage pathway emerging in saidreceiving receptacle and in said fastening platen to form a portion ofsaid discharge duct.
 11. The multiaxial pivoting head according to claim1, further comprising a water pressurizing device coupled to saidwaterjet cutting device, and wherein said water pressurizing device isable to be housed inside said moving arm.